The present invention relates to a dual-frequency antenna for mobile phone, and more particularly to a dual-frequency antenna formed from an integrally stamped thin metal conductor to enable quick connection of the antenna at a lower connector to a mobile phone and accurate controlling of the antenna frequencies.
FIGS. 1 and 2 are exploded and assembled perspective views, respectively, of a conventional antenna for mobile phone. The conventional antenna for mobile phone mainly includes two spring coils 10, 20 having large and small coil sizes, respectively, for putting around outer and inner wall surfaces, respectively, of a hollow insulting sleeve 30, and a link 40 connected to a bottom of the sleeve 30. The sleeve 30 is then covered with a protective casing (not shown). Through frequency matching and selection for the two spring coils 10, 20 at outer and inner sides of the insulating sleeve 30, the antenna is adapted to use with a dual-frequency mobile phone.
The spring coils 10, 20 are usually ready-made products. They are manufactured by winding wires around dies and manually adjusting the dies from time to time for the resultant spring coils 10, 20 to meet required specifications, including wire gauge for forming the spring coil, the coil size, the coil spacing, and the length of the coil. It is possible to effectively control such specifications when there is only a small quantity of spring coils to be produced through a die. However, when a large quantity of spring coils 10, 20 are produced, there would be difference in the specifications of the spring coils 10, 20 produced in different batches due to offset or deformation of dies having been used for a long time and some factors that could not be fully overcome in the manufacturing process. Spring coils 10, 20 that do not uniformly meet all the required specifications would inevitably adversely affect the accuracy of the antenna frequency. Moreover, the spring coils 10, 20 tend to compress and tangle with one another and become deformed during packing and transportation. The spring coils are subject to deformed coil spacing when an operator careless pulls the spring coils, making the antenna using these deformed coil springs failed to match the selected frequencies and resulted in poor signal receiving. The conventional antenna for mobile phone also includes complicate components and requires multiple steps to assemble the antenna and therefore need higher manufacturing costs.
It is therefore a primary object of the present invention to provide a dual-frequency antenna for mobile phone in which an integrally stamped thin metal conductor is included to function as a frequency-control structure of the antenna. An upper end of the stamped thin metal conductor is a curved wave coil and a lower end thereof is a connector having two hooks. The curved wave coil includes horizontal and vertical wave segments adapted to two different frequencies of 900 MHz and 1800 MHz, respectively. A cover encloses the curved wave coil to protect the coil against impact and deformation. The connector is adapted to insert into an antenna jack on a mobile phone to contact with a conductive leaf spring in the mobile phone, and the two hooks of the connector are adapted to firmly hold the whole antenna to the mobile phone.
Another object of the present invention is to provide a dual-frequency antenna that could be quickly and removably connected to a mobile phone. The antenna has a main body made of an integrally stamped thin metal conductor. A lower end of the main body forms a connector having two hooks provided at two sides thereof and two resilient pressing plates located above the two hooks and partially exposed from holes provided on a cover closing the main body. When the antenna is connected to a mobile phone, the two hooks abut against an inner wall of the mobile phone and hold the antenna to the phone. By depressing the two pressing plates, the two hooks are radially inward moved to separate from the inner wall of the mobile phone and thereby allow removal of the antenna from the mobile phone easily.